When Benazir Bhutto – then prime minister of Pakistan – announced she was pregnant with her second child in 1990, the opposition leader, Syeda Abida Hussain, accused her of being “greedy”. “It is clear she wants it all – motherhood, domesticity, glamour. She is even seeking more power than she has,” she said.

During the last trimester of her first pregnancy two years earlier, Bhutto, then opposition leader, had been a constant on the campaign trail as the country geared up for the first open election in more than a decade. This time, scared of being overthrown in her absence, she is said to have travelled in disguise to the hospital, where she had a caesarian section before returning to her desk the following day.

The fear of military coups aside, that’s how it was for expectant career women back then. You vomited quietly in the toilets, snuck off to ante-natal appointments as if they were extra-marital trysts and hoped no-one would hold your growing girth against you. It was the age of the “Supermums”: the Nicola Horlicks and the Karren Bradys who took an almost macho pride in being back in the office before their stitches had healed.

Thirty years on, the response to New Zealand prime minister Jacinda Ardern’s pregnancy has been largely positive. Indeed it has generated an air of national celebration, a bit like the south of England when another Royal baby has been conceived, but with less bunting.

Part of that was down to the upbeat tone in which Ardern announced it. “And we thought 2017 was a big year,” she tweeted breathlessly. “Clarke and I are really excited our team is about to expand from two to three.”

But it was also because the Labour prime minister has the potential to create a new climate in which women no longer have to hide the photographs of their babies in their desk drawer for fear of being judged.

True, Ardern kept her pregnancy secret for the first few months (when she first found out, she was in the middle of intense negotiations with eventual coalition partners New Zealand First). But now it’s public knowledge, she seems intent on turning parenthood into an asset and a key part of her legacy. Note, she didn’t say: “This pregnancy has no bearing on my ability to do my job”, but: “We will now join the many parents wearing two hats.” With these words, she not only forged a connection with ordinary working mothers, she made it clear that raising a child is an important job as opposed to something to be fitted into the corners of your day.

What made the announcement doubly remarkable was the casual way in which Ardern referred to her partner, Clarke Gayford, as the “primary care-giver”. Gayford, the presenter of a TV show about fishing, cultivates a hunter-gatherer image; his willingness to be a stay-at-home dad sends out a powerful message about what it means – and doesn’t mean – to be a man.

So how did New Zealand respond to the couple’s news? No-one appears to have batted an eyelid. TV crews interviewed everyone from punky young girls to bearded old geezers and they were universally unfazed. “Good luck to her,” was the general consensus.

Perhaps such a progressive attitude is to be expected in New Zealand, which is ahead of the curve on equality issues. In 1893, it became the first self-governing country in the world to give all women the vote.

Notwithstanding its three female prime ministers, however, New Zealand does have its flaws. Its gender pay gap – though smaller than in many countries’ – still stands at around nine per cent, and there is only one female chief executive officer among the 50 companies on its main stock market index. Ardern – at 37, the country’s youngest ever prime minister – has pledged to end the gender pay gap within four years and spoken out strongly on the need for more women in politics.

But it is on the rights of working mothers that she has been most vocal. Days after she was elected Labour leader in August, she rebuked chat-show host Mark Richardson for suggesting New Zealanders had a right to know if she was likely to be taking maternity leave while in office. “If you are an employer of a company you need to know that kind of thing,” he said.

Visibly angry, Ardern replied that while it was acceptable to ask about her own plans – because she had made it clear she was prepared to answer – it was unacceptable to ask questions of other women in the workplace.

One of the first pieces of legislation Ardern’s government introduced involved extending paid parental leave from 18 to 22 weeks from July, 2018 and to 26 weeks from July, 2020.

Such a focus on parental rights could come across as self-serving (though Ardern’s baby is due in June, so she is unlikely to benefit from the new policy). But even in 2018, her pregnancy, and subsequent baby, presents an opportunity to transform the way we view and treat working mothers.

As Nicola Sturgeon tweeted: “It demonstrates to young women that holding leadership positions needn’t be a barrier to having children (if you want to).”

Too often, when we listen to career women reflecting on past experiences of early motherhood, they are tinged with sadness. Karren Brady has said she regrets having returned to the Birmingham City boardroom three days after giving birth. “Phrases such as work/life balance didn’t exist 16 years ago,” she said in 2013. “I put [pressure] on myself because I wanted to be the perfect mother, the perfect employee, the perfect boss.”

Harriet Harman has spoken of feeling constantly scrutinised. “I was on the defensive all the time. I thought people were thinking ‘pregnant, baby, pregnant, baby, pregnant, baby – she’s not going to be doing her job properly.’ I had to prove myself all the time.”

Ardern, who is taking six weeks’ maternity leave, has the chance to change all that, not just for herself, but for those who follow. She can embrace a new kind of working motherhood: one in which raising children while pursuing a career is a badge of pride, not a source of shame; where everyone accepts it’s difficult to juggle competing demands, instead of pretending it’s a skoosh, where society is structured in such a way that the responsibility for caring is shared out, not dumped on one (generally female) set of shoulders.

Riffing on the “it takes a village” proverb, Ardern said: “New Zealand will help us raise our child.” A naïve hope, perhaps. But last week, it certainly seemed as if the whole country was behind her. Long may that positivity endure.